This invention relates to a small watercraft including a hull carrying propulsion means, and more particularly it is concerned with a device for increasing the stability of such watercraft when it is stationary.
In a small watercraft accommodating only one or two persons suitable for use in enjoying motorboating at leisure, particularly a high-speed watercraft of the compact size, it is essential that the width of its hull be minimized to increase its mobility, so long as the area of the bottom of the hull is large enough to ensure that the watercraft cruises smoothly on the water. Even if the beam of the hull is minimized as aforesaid, a lift is produced in the hull by the dynamic pressure of the water acting on the bottom of the hull when the watercraft is cruising, thereby enabling the watercraft to move smoothly while maintaining its stability. However, when the watercraft having a hull of a small width is stationary, the stability of the watercraft is low, and the watercraft may capsize if one tries to get aboard carelessly because of unstability of the watercraft stemming from a lack of enough buoyancy. To obviate this disadvantage, if the size of the hull is increased so as to enable a sufficiently high buoyancy to accommodate the weight of a person or persons as the case may be, an increase in the size of the hull causes a reduction in the gliding performance of the watercraft owing to an increase in the resistance offered by the water brought about by an increase in the area of the portion of the hull in contact with the water, an increase in the weight of the hull, an increase in production cost, and inconvenience in transporting the watercraft on land.